Electric mercury bulb switch



Nov. 21, 1933. MccABE ELECTRIC MERCURY BULB SWITCH Filed April 26, 1929Fig.12

INVENTOR IRA E M CABE ya ATTORNEY Patented Nov. 21, 1933 UNITED STATESPATENT OFFICE ELECTRIC MERCURY BULB swrron Ira E. McOabc, Chicago, 111.Application April as, 1929. Serial No. 358,225

4 Claims. (or. 200-152) This invention relates to improvements inelectric mercury bulb switches and more particularly to an improvedmanner in sealing the open end and positioning the leading inwirestherein.

It is an object of this invention to provide an electric switch of themercury type in which a glass bulb is manipulated by machinery tosupport the leading in wires in the sealed closed end of the bulb bypressing the glass about the wires in such a manner as to not only allowthe connecting leads to be brought back upon themselves to lead out fromthe bulb adjacent its longitudinal center but also to so form the sealedend of the bulb to form protecting projections between which theconnecting portions of the lead connections are received and held.

The particular bulb switch is of the same general type as that describedin my prior pending application, Serial No. 329,548, filed December 31,1928, and possesses all the advantages as set forth in said applicationand is a continuation of said invention in that the formation of the endseal of the bulb as disclosed herein provides decided advantages in themanner of attaching the connecting leads, aifords protection to suchattachment, maintains such attachment, insulates the connections of therespective leading in wires to the connecting leads, and directs thedeparting portions of the connecting leads toward the middle of thebulb, whereby when the bulb is mounted in a tiltable support theconnecting leads, departing from adjacent the pivot point of the bulb donot impede its movement.

With these and other objects in view, reference is made to theaccompanying sheet of drawing which illustrates preferred forms of thisinvention with the understanding that minor detail changes may be madewithout departing from the scope thereof.

In the drawing:

Figure 1 is a longitudinal horizontal sectional view, taken on the line11, Figure 2, of one embodiment of this invention.

Figure 2 is a view in elevation of the sealed. end of the bulb switch.

Figure 3 is a view in side elevation of the same.

Figure 4 is a view similar to Figure 2 illustrating the connecting leadssecured in place.

Figure 5 is a view in side elevation of Figure 4.

Figure 6 is a view in side elevation of a modified form of bulb switch.

Figure 7 is a top plan view of Figure 6 with the connecting leadssecured in place, and parts or the-bu1b brokenaway.

Figure 8 is a view in end elevation of Figure 7.

Figure 9 is a view in end elevation of another modification.

Figure 10 is a view in side elevation of Figure'9.

Figure 11 is a view in end elevation of a fur- 8o leading in wires 2 and3 and a filling stem 4,

heated and the heated walls pressed together to seal the leading inwires and stem, as described in said prior application Serial No.329,548.

In this instance the leading in wires are arranged in pairs. The twowires forming the upper pair 2 are parallel to each other, enter thesolid pressed end of the bulb above and in parallel relation to thelongitudinal center line of the bulb and then a short distance from thesealed end are bent toward each other and downward to enter within a cup5 of insulation material. The lower pair of leading in wires 3 areformed in one piece bent back upon itself in a loop within the bulb, theends are parallel to each other,

enter the solid pressed end of the bulb below and 30 in parallelrelation to the longitudinal center line of the bulb, and a shortdistance from the sealed end are bent downward and toward each other toengage and support the cut 5 so that its open top slopes downward towardthe lower opposite end of the bulb and then the wires are extendedparallel to the bottom of the bulb and out of engagement therewith to apoint beyond its longitudinal vertical center, in the manner describedin my prior application Serial Nos. 237,632 which became Patent No.1,757,436 May' 6, 1930 and 290,287, filed July 4, 1928.

When describing the above leading in wires 2 and 3, it is with theunderstanding that this term applies to the usual construction of bothleading in wires and electrodes welded thereto, as is customary, and asdescribed in my prior Patent No. 1,705,989, dated March 19, 1929.

The particular feature of this invention resides in the formation of theclosed or sealed end of stated in forming the construction .01 thecompleted bulb switch, the open end of the bulb is heated until itbecomes plastic and then is I clamped about the leading in wires andfilling stem. In this instance the plastic walls of the open end of thebulb are brought together by clamping in the form 01' a cross, as shownin Figure 2 oi the drawing, whereby the equidistant and oppositelydisposed right angular depressions 8 form walls to embrace and seal thefilling stem and each of'the respective lead wires so that thefilling'stem and lead wires are each sealed within the closed end or thebulb in the same manner as described in my prior application, Serial No.329,548, except that the filling stem is enclosed in the center or mainportion of the closed end, and each leading in wire is enclosedandsupported in a radial portion '7, as shown. As illustrated in Figure 3,each leading in wire of the pairs 2 and 3 extend slightly beyond theoutside of the closed end portion, and the filling stem 4 is tipped ofla slight distance beyond the exterior terminations of the lead in wires.The connecting leads are preferably formed of tubular wires braidedtogether as described in Patent No. 1,640,- 869, dated August 30, 1927,and each connecting lead is connected or joined to each exterior end oreach leading in wire in the manner described in said patent. After theconnecting leads are secured in place, each one is bent back upon itselfover the radial portion 7 of the sealed end embracing its respectiveleading in wire. The body of said connecting lead being received withinthe right angular depression 6 adjacent said radial portion, as clearlyshown in Figure 5. A sleeve of any desired material is then placed overthe sealed end to snugly engage the outer terminations of the radialportions, and is aflixed thereto either by the tension oi. the sleeve orby cementitious material whereby the connecting leads are held in placeas shown in Figures 4 and 5.

Figures 6, '1 and 8 illustrate a three wire mercury bulb switch whereina pair of lead wires 2' enter the closed end and are sealed thereinsimilarly to the leading in wires 2, illustrated in Figure 1. In thiscase a single lead wire 3' enters below and in a plane passing throughthe vertical longitudinal center line of the bulb 1, which leading inwire is bent upward as it leaves the interior oi the seal and thendownwardly in the direction of the opposite lower end of the bulb. Inthis particular form the leading in wire is curved to engage andposition the cup of insulating material upon one side thereof to supportthe open end of said cup sloping in the direction of the opposite lowerend of the bulb 1. The leading in wire is then continued parallel to thebottom of the bulb until adjacent the closed end, and is then bentupward and around the exterior of a second cup 5' oi insulating materialto engage and support this second cup with its open end sloping in thedirection of the bottom of the opposite sealed end of the bulb, and thewire is then continued parallel to the bottom of the bulb to engage andpass about the first cup 5 until it meets the other portion thereof, andis attached thereto. In this type the plastic open end of the bulb 1 ispressed about the filling stem 4 to form radial portions 7' embracingand sealing the three leading in wires as shown in Figure 8. One of theupper leading in wires 2' is bent downwardly at right angles to enterthe interior of the cup 5 and the other of this pair is extended'andthen bent downwardly to enter the other cup 5'. In this form the leadconnections 8 are connected or joined to the exterior portions of theleading in wires in the same mannerasinthefirstiormandeachotthese leadconnections are bent back upon itself and is received within thedepression between the radial portions and a securing sleeve 8 is placedabout the radial portions of the sealed end in the same manner asdescribed'in connection with the firstiorm,andasshowninFigures7and8.

Figures 9 and 10 illustrate the application of this invention to anothertype of bulb switch in which four leading inwires 9, 10, 11 and 12 areprovided which enter the sealed end in parallel relation to thelongitudinal center line thereof but which areal-ranged in planes atright angles 'to each other as shown in Figure 9. In this form thelowermost leading in wire 11 extends within the bulb to approximatelyits middle portion. The uppermost leading in wire 9 extends within thebulb to a point adjacent the closed end, and then is bent downwardly atright angles to a point adjacent its bottom wall. The two leading inwires 10 and 12 arranged in the plane at right angles to the plane ofthe wires just described, each extend within the bulb and are then bentdownwardly at right angles to a point adjacent the bottom wall and insuch relation that an equal space separates the terminations betweeneach of the four leading in wires, as shown in Figure 10.

Figures 11 and 12 illustrate another type of mercury bulb switchconstructed somewhat similarly to that illustrated in Figures 9 and 10with the exception that the lowermost lead 11 is terminated in anenlarged electrode 13 adjacent the sealed end, and the two leading inwires 10 and 12 arranged in the plane at right angles to the plane orthe upper and lower leading in wires are both bent downwardly atapproximately the same distance from the sealed end, and the upperleading in wire 9 is bent downwardly and provided with an enlargedelectrode 13 at approximately the middle portion of the interior of thebulb, so that the terminations of the pair of leading in wires 10 and 12arranged in the plane at right angles to the plane of the upper andlower leading in wires are approximately equidistant from the enlargedelectrodes 01' said upper and lower leading in wires as shown in Figure12. In this type of switch, as shown in Figures 9, 10, 11 and 12, theconnecting leads are secured in the same manner as heretofore describedto the exterior portions of the said leading in wires, and are bent backupon themselves and enclosed in a surrounding sleeve in the same manneras shown in Figures 5 and 7.

In as much as mercury switches of this general type are well known inthis art and the operation of the same as applied to the first eightfigures of the drawing have been described in my prior co-pendingapplications, a further description is not deemed necessary. It isreadily seen that in Figure 10 when the bulb is tilted in the mannershown in said figure, the body of mercury flows toward the sealed endand covers the lowermost electrode, or leading in wire 11, while theother three electrodes are uncovered, and therefore the circuit isbroken through the switch. As the switch is tilted in the oppositedirection, and the mercury flows toward the closed end oi! the bulb,opposite the sealed end, three circuits will be consecutively closedbetween the lowermost leading in wire as the mercury contacts andembraces the lower extremities of each of the other three leading inwires respectively.

Theadvantagesof my improved construction are many. It permits the use ofbulbs for making the mercury switch instead of tubing. It has long beencustomary to make use of glass tubing for the construction of mercuryswitches. I refer to my prior Patents Nos. 1,658,013, January 31, 1928;1,662,122, March 15, 1928; 1,674,601, June 19, 1928; and 1,705,989,March 19, 1929, and Patent 1,757,436, May 6, 1930, in which a tippingoiI of the tube at each end of the switch is the usual practice. Theadoption of a bulb has long been desirable. Bulbs are blown in machinerywith the aid of molds which permit the maintaining of more accurate anduniform standards, and reduce the amount of material necessary toproduce them as compared with the tube type. Furthermore, in the use ofthe old style tip type tube, it has always been necessary to tubulatethe end with a filling stem, with a constriction whereby additionaloperations became necessary to produce them. In my design the only glassneeded is the bulb which comes from a bulb blowing machine ready to beused, and a piece of straight glass tubing which serves as the fillingand sealing oif stem. Also where necessary a bead is used on the variouselectrodes. The entire assembly including electrodes, filling stem andbulb is sealed and blow in one operation. This permits of greateconomies in manufacture since automatic machinery may be used toproduce the device, also the standard of manufacture may be readilymaintained due to the design of the various parts. These standards aremaintained in 1,757,436, May 6, 1930, a limited number of termer methodsand structure. In my Patent 1,757,436 May 6, 1930, a limited number ofterminals or leading in wires were provided. In this application thescope of the design has been greatly extended and made practical due tothe separation of the various sealing in wires.

What I claim is:

1. An electric bulb switch including a tubular glass bulb containing aquantity of mercury and a plurality of more than two leading in wiresentering the interior of the bulb in parallel relation to itslongitudinal center line, the open end of the bulb closed to provide aplurality of radial portions in the walls thereof each embracing andsealing a respective leading in wire, connecting leads joined to eachrespective leading in wire, each lead bent back upon itself to contactthe walls between two adjacent radial portions, and a sleeve surroundingthe respective bent back connecting leads and engaging the outerextremities of said radial portions of said closed end.

2. An electric bulb switch including a tubular bulb of insulatingmaterial containing a quantity of electrical conducting fluid, aplurality of more then two leading in wires and a filling stem enteringthe interior of the bulb, the leading in wires in parallel relation toits longitudinal center line and the stem on said center line, and theside walls of the bulb about the open end of the bulb brought togetherand closed about said leading in wires and filling stem to separatelyembrace and seal each leading in wire in equally spaced relation to eachother at the same distance from said stem.

3. An electric bulb switch including a tubular glass bulb containing aquantity of mercury and a plurality of more than two leading in wiresentering the interior of the bulb in parallel relation to andequidistant from its longitudinal center line and a filling stemarranged on said center line, the side walls about the open end of thebulb brought together and closed about said leading in wires and stem toprovide a plurality of prolonged radial portions each embracing and '100sealing a respective leading in wire, connecting leads joined to contactthe walls and each respective leading in wire, each lead bent back uponitself to be received between two adjacent radial portions, and a sleevesurrounding the respective bent back connecting leads and engaging theouter extremities of said radial portions of said closed end to hold theconnecting leads first against the stem and then between said radialportions.

4. An electric bulb switch including a tubular glass bulb containing aquantity of mercury and four leading in wires entering the interior ofthe bulb in parallel relation to its longitudinal center line with afilling stem entering the interior 1 5 of the bulb upon its longitudinalcenter line, the walls about the open end of the bulb brought togetherand closed to embrace and seal the filling stem and to provide fourintegral radial extending portions each embracing and sealing arespective leading in wire, said filling stem closed and said leading inwires terminated in line with the exterior of the closed filling stem,connecting leads joined to each respective leading in wire and each leadbent back upon itself to engage the wall between two adjacent radialportions, and a sleeve binding the radial portions and holding therespective leads from displacement.

CERTIFICATE or CORRECTION.

Patent No. 1,936,094. November 21, 1933.

IRA E. McCABE.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring'correction as follows: Page 1,line 84, for "cut" read cup; page 3, line 30, for "blow" read blown; andline 36, strike out the number and words "1,757,436, May 6, 1930, alimited number of ter-" and insert instead a manner not possible orpractical with the for-; and that the said Letters Patent should be readwith these corrections therein that the same may conform to the recordof the case in the Patent Office.

Signed and sealed this 6th day of March, A. D. 1934.

F. M. Hopkins (Seal) Acting Commissioner of Patents.

